Evaluate the protective qualities of the captcha

I’m learning how to write captcha on the site, I don’t want to use ready-made solutions, I want to learn it myself. I think you understand me. Found a tutorial on creating a captcha. Can you please tell me if this captcha can be used on serious projects? That is, will it protect against spam?

Tutorial at this link:

Creating a PHP Captcha

Answer 1, authority 100%

It depends what you mean by spam. If robots use a form protected by this captcha, then don’t rely on it too much. It is better to protect yourself from robots with additional fields hidden from users via CSS

Answer 2

Captcha protects perfectly only when no one knows about it, as soon as it becomes popular and becomes popular, bots write for it.

More or less (IMHO) working method is a unique question-answer, everything else is crap.

Answer 3

Captcha is a dead end approach. Need something new! 🙂

PS: on the topic, the captcha is elementary, it breaks without any problems using standard tools 🙂